Re: mod_perl caching

Check out the Apache::Reload module. It allows code in your .pm files to be recompiled automatically when a change to the file is detected - essential for development.

Update: When I do need to do a graceful restart on the Apache server (eg: to pick up changes to the config file) I tend not to use apachectl directly. If there is a bug in your code or config, it won't be detected until the server tries (and fails) to restart. This leaves you with two problems: the server is down and you have broken code which must be fixed before the server will start. Pressure!

A safer option is to use a custom script which first does a syntax check of you httpd.conf and any Perl modules it loads. If that succeeds that it's safe to call apachctl. Here's the relevant part of my initserver script:

#!/bin/sh

SERVER="/usr/sbin/httpd"
CONFIG="/etc/httpd/conf/httpd.conf"

ARGS=`/bin/ls /usr/lib/apache | perl -nle 'm{^(?:mod_|lib)(.*?)(\.so)?
+$} && print uc("-DHAVE_$1")'`

if ! $SERVER -T $ARGS -f $CONFIG
then
  echo "Server not restarted due to errors in config file"
  exit 1
fi

apachectl graceful
[download]

The ARGS=... line adds command line arguments like -DHAVE_PERL, -DHAVE_REWRITE etc for all the modules which are loaded dynamically. You may or may not need that.

Comment on Re: mod_perl caching Download Code

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Re: Re: mod_perl caching by jms1 (Initiate) on Apr 02, 2003 at 08:47 UTC
more specifically (from a development site on my own web server): in the httpd.conf file, inside of a container (either <Location>, <Directory>, or <VirtualHost>) add these lines: `PerlModule Apache::Reload PerlInitHandler Apache::Reload PerlSetVar ReloadAll Off PerlSetVar ReloadTouchFile /tmp/reload.modules` [download] the way it works is this: the first time each module is loaded (or if the module is already in memory, used) mod_perl will check the date/time of the given file. if it has changed since the last time it was parsed, the parsed code in memory will be unloaded and the code will be re-parsed from the disk. the problem is that doing this check for every module, for every request, causes a signifigant slowdown on a busy server. setting "ReloadAll Off" turns off the global checking, and the check will only be done for modules which contain the line "use Apache::Reload" in their code. note that this also works for authentication handlers, in addition to standard content-generation handlers. my guess is that it will work with all handlers, regardless of the request phase they handle, but i've only used it with these two types.	[reply] [d/l]

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Re: Re: mod_perl caching
by jms1 (Initiate) on Apr 02, 2003 at 08:47 UTC

PerlModule       Apache::Reload
PerlInitHandler  Apache::Reload
PerlSetVar       ReloadAll Off
PerlSetVar       ReloadTouchFile /tmp/reload.modules
[download]

the problem is that doing this check for every module, for every request, causes a signifigant slowdown on a busy server.

setting "ReloadAll Off" turns off the global checking, and the check will only be done for modules which contain the line "use Apache::Reload" in their code.

note that this also works for authentication handlers, in addition to standard content-generation handlers. my guess is that it will work with all handlers, regardless of the request phase they handle, but i've only used it with these two types.

[reply]
[d/l]